diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index d0e34c8c45fe7f7eb9671b1b11f219966a803003..fd231baa49680d14cfb0550837070e063409bb7a 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,16 @@
+2005-09-27 Jeff Law <law@redhat.com>
+
+ * passes.c (init_optimization_passes): Replace copy propagation
+ passes immediately after DOM with phi-only copy propagation
+ pases. Add phi-only copy propagation pass after first DOM pass.
+ * tree-pass.h (pass_phi_only_copy_prop): Declare.
+ * tree-ssa-copy.c (init_copy_prop): Accept new PHI_ONLY argument.
+ If true, then mark all non-control statements with DONT_SIMULATE_AGAIN.
+ (execute_copy_prop): Accept new PHI_ONLY argument. Pass it along
+ to init_copy_prop. Callers updated.
+ (do_phi_only_copy_prop): New function.
+ (pass_phi_only_copy_prop): New pass descriptor.
+
2005-09-27 Nick Clifton <nickc@redhat.com>
* libgcc2.c (__popcount_tab): Remove redundant prototype.
diff --git a/gcc/passes.c b/gcc/passes.c
index 6a35b1750a7cbe14e62c320f0b15c6aa049a40c4..b03eae39f4398033943c2baebb4cf7053c545432 100644
--- a/gcc/passes.c
+++ b/gcc/passes.c
@@ -494,6 +494,12 @@ init_optimization_passes (void)
NEXT_PASS (pass_merge_phi);
NEXT_PASS (pass_dominator);
+ /* The only copy propagation opportunities left after DOM
+ should be due to degenerate PHI nodes. So rather than
+ run the full copy propagator, just discover and copy
+ propagate away the degenerate PHI nodes. */
+ NEXT_PASS (pass_phi_only_copy_prop);
+
NEXT_PASS (pass_phiopt);
NEXT_PASS (pass_may_alias);
NEXT_PASS (pass_tail_recursion);
@@ -508,7 +514,13 @@ init_optimization_passes (void)
NEXT_PASS (pass_may_alias);
NEXT_PASS (pass_rename_ssa_copies);
NEXT_PASS (pass_dominator);
- NEXT_PASS (pass_copy_prop);
+
+ /* The only copy propagation opportunities left after DOM
+ should be due to degenerate PHI nodes. So rather than
+ run the full copy propagator, just discover and copy
+ propagate away the degenerate PHI nodes. */
+ NEXT_PASS (pass_phi_only_copy_prop);
+
NEXT_PASS (pass_dce);
NEXT_PASS (pass_dse);
NEXT_PASS (pass_may_alias);
@@ -529,7 +541,13 @@ init_optimization_passes (void)
NEXT_PASS (pass_sink_code);
NEXT_PASS (pass_tree_loop);
NEXT_PASS (pass_dominator);
- NEXT_PASS (pass_copy_prop);
+
+ /* The only copy propagation opportunities left after DOM
+ should be due to degenerate PHI nodes. So rather than
+ run the full copy propagator, just discover and copy
+ propagate away the degenerate PHI nodes. */
+ NEXT_PASS (pass_phi_only_copy_prop);
+
NEXT_PASS (pass_cd_dce);
/* FIXME: If DCE is not run before checking for uninitialized uses,
diff --git a/gcc/tree-pass.h b/gcc/tree-pass.h
index 57dc029438eeea05da849250a3cebb600819dc22..6674884944a7f4a01d384dad7bd9c2e4fee04fd4 100644
--- a/gcc/tree-pass.h
+++ b/gcc/tree-pass.h
@@ -275,6 +275,7 @@ extern struct tree_opt_pass pass_sink_code;
extern struct tree_opt_pass pass_fre;
extern struct tree_opt_pass pass_linear_transform;
extern struct tree_opt_pass pass_copy_prop;
+extern struct tree_opt_pass pass_phi_only_copy_prop;
extern struct tree_opt_pass pass_store_ccp;
extern struct tree_opt_pass pass_store_copy_prop;
extern struct tree_opt_pass pass_vrp;
diff --git a/gcc/tree-ssa-copy.c b/gcc/tree-ssa-copy.c
index 47ac55f3b5fad14f347c6c560be12905c8fd2933..575fe09d6e47ece6aadb1bee23f6bee5be2a213e 100644
--- a/gcc/tree-ssa-copy.c
+++ b/gcc/tree-ssa-copy.c
@@ -838,10 +838,12 @@ copy_prop_visit_phi_node (tree phi)
}
-/* Initialize structures used for copy propagation. */
+/* Initialize structures used for copy propagation. PHIS_ONLY is true
+ if we should only consider PHI nodes as generating copy propagation
+ opportunities. */
static void
-init_copy_prop (void)
+init_copy_prop (bool phis_only)
{
basic_block bb;
@@ -866,7 +868,7 @@ init_copy_prop (void)
lists of the propagator. */
if (stmt_ends_bb_p (stmt))
DONT_SIMULATE_AGAIN (stmt) = false;
- else if (stmt_may_generate_copy (stmt))
+ else if (!phis_only && stmt_may_generate_copy (stmt))
DONT_SIMULATE_AGAIN (stmt) = false;
else
{
@@ -917,10 +919,15 @@ fini_copy_prop (void)
}
-/* Main entry point to the copy propagator. The algorithm propagates
- the value COPY-OF using ssa_propagate. For every variable X_i,
- COPY-OF(X_i) indicates which variable is X_i created from. The
- following example shows how the algorithm proceeds at a high level:
+/* Main entry point to the copy propagator.
+
+ PHIS_ONLY is true if we should only consider PHI nodes as generating
+ copy propagation opportunities.
+
+ The algorithm propagates the value COPY-OF using ssa_propagate. For
+ every variable X_i, COPY-OF(X_i) indicates which variable is X_i created
+ from. The following example shows how the algorithm proceeds at a
+ high level:
1 a_24 = x_1
2 a_2 = PHI <a_24, x_1>
@@ -1020,10 +1027,10 @@ fini_copy_prop (void)
x_53 and x_54 are both copies of x_898. */
static void
-execute_copy_prop (bool store_copy_prop)
+execute_copy_prop (bool store_copy_prop, bool phis_only)
{
do_store_copy_prop = store_copy_prop;
- init_copy_prop ();
+ init_copy_prop (phis_only);
ssa_propagate (copy_prop_visit_stmt, copy_prop_visit_phi_node);
fini_copy_prop ();
}
@@ -1038,7 +1045,7 @@ gate_copy_prop (void)
static void
do_copy_prop (void)
{
- execute_copy_prop (false);
+ execute_copy_prop (false, false);
}
struct tree_opt_pass pass_copy_prop =
@@ -1063,6 +1070,34 @@ struct tree_opt_pass pass_copy_prop =
};
+static void
+do_phi_only_copy_prop (void)
+{
+ execute_copy_prop (false, true);
+}
+
+struct tree_opt_pass pass_phi_only_copy_prop =
+{
+ "phionlycopyprop", /* name */
+ gate_copy_prop, /* gate */
+ do_phi_only_copy_prop, /* execute */
+ NULL, /* sub */
+ NULL, /* next */
+ 0, /* static_pass_number */
+ TV_TREE_COPY_PROP, /* tv_id */
+ PROP_ssa | PROP_alias | PROP_cfg, /* properties_required */
+ 0, /* properties_provided */
+ 0, /* properties_destroyed */
+ 0, /* todo_flags_start */
+ TODO_cleanup_cfg
+ | TODO_dump_func
+ | TODO_ggc_collect
+ | TODO_verify_ssa
+ | TODO_update_ssa, /* todo_flags_finish */
+ 0 /* letter */
+};
+
+
static bool
gate_store_copy_prop (void)
{
@@ -1077,7 +1112,7 @@ static void
store_copy_prop (void)
{
/* If STORE-COPY-PROP is not enabled, we just run regular COPY-PROP. */
- execute_copy_prop (flag_tree_store_copy_prop != 0);
+ execute_copy_prop (flag_tree_store_copy_prop != 0, false);
}
struct tree_opt_pass pass_store_copy_prop =